/*
 * note "shell - top" related file
 * Copyright (C) 2019 Dramalife <dramalife@live.com>
 * 
 * This file is part of [note](https://github.com/Dramalife/note.git)
 * 
 * note is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * $ gcc --version
 * gcc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0
 * Copyright (C) 2017 Free Software Foundation, Inc.
 * This is free software; see the source for copying conditions.  There is NO
 * warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * ;
 * 
 * $ uname -a
 * Linux iZ2zeeq1jai7e6qn7xqrnuZ 4.15.0-96-generic #97-Ubuntu SMP Wed Apr 1 03:25:46 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
 * ;
 * 
 * Init : Thu Dec 31 22:35:14 CST 2020
 * 	COPY FROM : https://blog.csdn.net/earbao/article/details/43453111;
 *  
 * Update
 *
 */

/*
 * Copyright (c) 2008, The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the 
 *    distribution.
 *  * Neither the name of Google, Inc. nor the names of its contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <dirent.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>

//#include <cutils/sched_policy.h>
/**
  typedef enum {
  SP_BACKGROUND = 0,
  SP_FOREGROUND = 1,
  } SchedPolicy;
 */
//extern int get_sched_policy(int tid, SchedPolicy *policy);

struct cpu_info {
	long unsigned utime, ntime, stime, itime;
	long unsigned iowtime, irqtime, sirqtime;
};

#define PROC_NAME_LEN 64
#define THREAD_NAME_LEN 32

struct proc_info {
	struct proc_info *next;
	pid_t pid;
	pid_t tid;
	uid_t uid;
	gid_t gid;
	char name[PROC_NAME_LEN];
	char tname[THREAD_NAME_LEN];
	char state;
	long unsigned utime;
	long unsigned stime;
	long unsigned delta_utime;
	long unsigned delta_stime;
	long unsigned delta_time;
	long vss;
	long rss;
	int num_threads;
	char policy[32];
};

struct proc_list {
	struct proc_info **array;
	int size;
};

#define die(...) { fprintf(stderr, __VA_ARGS__); exit(EXIT_FAILURE); }

#define INIT_PROCS 50
#define THREAD_MULT 8
static struct proc_info **old_procs, **new_procs;
static int num_old_procs, num_new_procs;
static struct proc_info *free_procs;
static int num_used_procs, num_free_procs;

static int max_procs, delay, iterations, threads;

static struct cpu_info old_cpu, new_cpu;

static struct proc_info *alloc_proc(void);
static void free_proc(struct proc_info *proc);
static void read_procs(void);
static int read_stat(char *filename, struct proc_info *proc);
static void read_policy(int pid, struct proc_info *proc);
static void add_proc(int proc_num, struct proc_info *proc);
static int read_cmdline(char *filename, struct proc_info *proc);
static int read_status(char *filename, struct proc_info *proc);
static void print_procs(void);
static struct proc_info *find_old_proc(pid_t pid, pid_t tid);
static void free_old_procs(void);
static int (*proc_cmp)(const void *a, const void *b);
static int proc_cpu_cmp(const void *a, const void *b);
static int proc_vss_cmp(const void *a, const void *b);
static int proc_rss_cmp(const void *a, const void *b);
static int proc_thr_cmp(const void *a, const void *b);
static int numcmp(long long a, long long b);
static void usage(char *cmd);

int main(int argc, char *argv[]) {
	int i;

	num_used_procs = num_free_procs = 0;

	max_procs = 0;
	delay = 3;
	iterations = -1;
	proc_cmp = &proc_cpu_cmp;
	for (i = 1; i < argc; i++) {
		if (!strcmp(argv[i], "-m")) {
			if (i + 1 >= argc) {
				fprintf(stderr, "Option -m expects an argument.\n");
				usage(argv[0]);
				exit(EXIT_FAILURE);
			}
			max_procs = atoi(argv[++i]);
			continue;
		}
		if (!strcmp(argv[i], "-n")) {
			if (i + 1 >= argc) {
				fprintf(stderr, "Option -n expects an argument.\n");
				usage(argv[0]);
				exit(EXIT_FAILURE);
			}
			iterations = atoi(argv[++i]);
			continue;
		}
		if (!strcmp(argv[i], "-d")) {
			if (i + 1 >= argc) {
				fprintf(stderr, "Option -d expects an argument.\n");
				usage(argv[0]);
				exit(EXIT_FAILURE);
			}
			delay = atoi(argv[++i]);
			continue;
		}
		if (!strcmp(argv[i], "-s")) {
			if (i + 1 >= argc) {
				fprintf(stderr, "Option -s expects an argument.\n");
				usage(argv[0]);
				exit(EXIT_FAILURE);
			}
			++i;
			if (!strcmp(argv[i], "cpu")) { proc_cmp = &proc_cpu_cmp; continue; }
			if (!strcmp(argv[i], "vss")) { proc_cmp = &proc_vss_cmp; continue; }
			if (!strcmp(argv[i], "rss")) { proc_cmp = &proc_rss_cmp; continue; }
			if (!strcmp(argv[i], "thr")) { proc_cmp = &proc_thr_cmp; continue; }
			fprintf(stderr, "Invalid argument \"%s\" for option -s.\n", argv[i]);
			exit(EXIT_FAILURE);
		}
		if (!strcmp(argv[i], "-t")) { threads = 1; continue; }
		if (!strcmp(argv[i], "-h")) {
			usage(argv[0]);
			exit(EXIT_SUCCESS);
		}
		fprintf(stderr, "Invalid argument \"%s\".\n", argv[i]);
		usage(argv[0]);
		exit(EXIT_FAILURE);
	}

	if (threads && proc_cmp == &proc_thr_cmp) {
		fprintf(stderr, "Sorting by threads per thread makes no sense!\n");
		exit(EXIT_FAILURE);
	}

	free_procs = NULL;

	num_new_procs = num_old_procs = 0;
	new_procs = old_procs = NULL;

	read_procs();
	while ((iterations == -1) || (iterations-- > 0)) {
		old_procs = new_procs;
		num_old_procs = num_new_procs;
		memcpy(&old_cpu, &new_cpu, sizeof(old_cpu));
		sleep(delay);
		read_procs();
		print_procs();
		free_old_procs();
	}

	return 0;
}

static struct proc_info *alloc_proc(void) {
	struct proc_info *proc;

	if (free_procs) {
		proc = free_procs;
		free_procs = free_procs->next;
		num_free_procs--;
	} else {
		proc = malloc(sizeof(*proc));
		if (!proc) die("Could not allocate struct process_info.\n");
	}

	num_used_procs++;

	return proc;
}

static void free_proc(struct proc_info *proc) {
	proc->next = free_procs;
	free_procs = proc;

	num_used_procs--;
	num_free_procs++;
}

#define MAX_LINE 256

static void read_procs(void) {
	DIR *proc_dir, *task_dir;
	struct dirent *pid_dir, *tid_dir;
	char filename[64];
	FILE *file;
	int proc_num;
	struct proc_info *proc;
	pid_t pid, tid;

	int i;

	proc_dir = opendir("/proc");
	if (!proc_dir) die("Could not open /proc.\n");

	new_procs = calloc(INIT_PROCS * (threads ? THREAD_MULT : 1), sizeof(struct proc_info *));
	num_new_procs = INIT_PROCS * (threads ? THREAD_MULT : 1);

	file = fopen("/proc/stat", "r");
	if (!file) die("Could not open /proc/stat.\n");
	fscanf(file, "cpu  %lu %lu %lu %lu %lu %lu %lu", &new_cpu.utime, &new_cpu.ntime, &new_cpu.stime,
			&new_cpu.itime, &new_cpu.iowtime, &new_cpu.irqtime, &new_cpu.sirqtime);
	fclose(file);

	proc_num = 0;
	while ((pid_dir = readdir(proc_dir))) {
		if (!isdigit(pid_dir->d_name[0]))
			continue;

		pid = atoi(pid_dir->d_name);

		struct proc_info cur_proc;

		if (!threads) {
			proc = alloc_proc();

			proc->pid = proc->tid = pid;

			sprintf(filename, "/proc/%d/stat", pid);
			read_stat(filename, proc);

			sprintf(filename, "/proc/%d/cmdline", pid);
			read_cmdline(filename, proc);

			sprintf(filename, "/proc/%d/status", pid);
			read_status(filename, proc);

			read_policy(pid, proc);

			proc->num_threads = 0;
		} else {
			sprintf(filename, "/proc/%d/cmdline", pid);
			read_cmdline(filename, &cur_proc);

			sprintf(filename, "/proc/%d/status", pid);
			read_status(filename, &cur_proc);

			proc = NULL;
		}

		sprintf(filename, "/proc/%d/task", pid);
		task_dir = opendir(filename);
		if (!task_dir) continue;

		while ((tid_dir = readdir(task_dir))) {
			if (!isdigit(tid_dir->d_name[0]))
				continue;

			if (threads) {
				tid = atoi(tid_dir->d_name);

				proc = alloc_proc();

				proc->pid = pid; proc->tid = tid;

				sprintf(filename, "/proc/%d/task/%d/stat", pid, tid);
				read_stat(filename, proc);

				read_policy(tid, proc);

				strcpy(proc->name, cur_proc.name);
				proc->uid = cur_proc.uid;
				proc->gid = cur_proc.gid;

				add_proc(proc_num++, proc);
			} else {
				proc->num_threads++;
			}
		}

		closedir(task_dir);

		if (!threads)
			add_proc(proc_num++, proc);
	}

	for (i = proc_num; i < num_new_procs; i++)
		new_procs[i] = NULL;

	closedir(proc_dir);
}

static int read_stat(char *filename, struct proc_info *proc) {
	FILE *file;
	char buf[MAX_LINE], *open_paren, *close_paren;
	int res, idx;

	file = fopen(filename, "r");
	if (!file) return 1;
	fgets(buf, MAX_LINE, file);
	fclose(file);

	/* Split at first '(' and last ')' to get process name. */
	open_paren = strchr(buf, '(');
	close_paren = strrchr(buf, ')');
	if (!open_paren || !close_paren) return 1;

	*open_paren = *close_paren = '\0';
	strncpy(proc->tname, open_paren + 1, THREAD_NAME_LEN);
	proc->tname[THREAD_NAME_LEN-1] = 0;

	/* Scan rest of string. */
	sscanf(close_paren + 1, " %c %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
			"%lu %lu %*d %*d %*d %*d %*d %*d %*d %lu %ld",
			&proc->state, &proc->utime, &proc->stime, &proc->vss, &proc->rss);

	return 0;
}

static void add_proc(int proc_num, struct proc_info *proc) {
	int i;

	if (proc_num >= num_new_procs) {
		new_procs = realloc(new_procs, 2 * num_new_procs * sizeof(struct proc_info *));
		if (!new_procs) die("Could not expand procs array.\n");
		for (i = num_new_procs; i < 2 * num_new_procs; i++)
			new_procs[i] = NULL;
		num_new_procs = 2 * num_new_procs;
	}
	new_procs[proc_num] = proc;
}

static int read_cmdline(char *filename, struct proc_info *proc) {
	FILE *file;
	char line[MAX_LINE];

	line[0] = '\0';
	file = fopen(filename, "r");
	if (!file) return 1;
	fgets(line, MAX_LINE, file);
	fclose(file);
	if (strlen(line) > 0) {
		strncpy(proc->name, line, PROC_NAME_LEN);
		proc->name[PROC_NAME_LEN-1] = 0;
	} else
		proc->name[0] = 0;
	return 0;
}

static void read_policy(int pid, struct proc_info *proc) {
	/**
	  SchedPolicy p;
	  if (get_sched_policy(pid, &p) < 0)
	  strcpy(proc->policy, "unk");
	  else {
	  if (p == SP_BACKGROUND)
	  strcpy(proc->policy, "bg");
	  else if (p == SP_FOREGROUND)
	  strcpy(proc->policy, "fg");
	  else
	  strcpy(proc->policy, "er");
	  }*/
}

static int read_status(char *filename, struct proc_info *proc) {
	FILE *file;
	char line[MAX_LINE];
	unsigned int uid, gid;

	file = fopen(filename, "r");
	if (!file) return 1;
	while (fgets(line, MAX_LINE, file)) {
		sscanf(line, "Uid: %u", &uid);
		sscanf(line, "Gid: %u", &gid);
	}
	fclose(file);
	proc->uid = uid; proc->gid = gid;
	return 0;
}

static void print_procs(void) {
	int i;
	struct proc_info *old_proc, *proc;
	long unsigned total_delta_time;
	struct passwd *user;
	struct group *group;
	char *user_str, user_buf[20];
	char *group_str, group_buf[20];

	for (i = 0; i < num_new_procs; i++) {
		if (new_procs[i]) {
			old_proc = find_old_proc(new_procs[i]->pid, new_procs[i]->tid);
			if (old_proc) {
				new_procs[i]->delta_utime = new_procs[i]->utime - old_proc->utime;
				new_procs[i]->delta_stime = new_procs[i]->stime - old_proc->stime;
			} else {
				new_procs[i]->delta_utime = 0;
				new_procs[i]->delta_stime = 0;
			}
			new_procs[i]->delta_time = new_procs[i]->delta_utime + new_procs[i]->delta_stime;
		}
	}

	total_delta_time = (new_cpu.utime + new_cpu.ntime + new_cpu.stime + new_cpu.itime
			+ new_cpu.iowtime + new_cpu.irqtime + new_cpu.sirqtime)
		- (old_cpu.utime + old_cpu.ntime + old_cpu.stime + old_cpu.itime
				+ old_cpu.iowtime + old_cpu.irqtime + old_cpu.sirqtime);

	qsort(new_procs, num_new_procs, sizeof(struct proc_info *), proc_cmp);

	printf("\n\n\n");
	printf("User %ld%%, System %ld%%, IOW %ld%%, IRQ %ld%%\n",
			((new_cpu.utime + new_cpu.ntime) - (old_cpu.utime + old_cpu.ntime)) * 100  / total_delta_time,
			((new_cpu.stime ) - (old_cpu.stime)) * 100 / total_delta_time,
			((new_cpu.iowtime) - (old_cpu.iowtime)) * 100 / total_delta_time,
			((new_cpu.irqtime + new_cpu.sirqtime)
			 - (old_cpu.irqtime + old_cpu.sirqtime)) * 100 / total_delta_time);
	printf("User %ld + Nice %ld + Sys %ld + Idle %ld + IOW %ld + IRQ %ld + SIRQ %ld = %ld\n",
			new_cpu.utime - old_cpu.utime,
			new_cpu.ntime - old_cpu.ntime,
			new_cpu.stime - old_cpu.stime,
			new_cpu.itime - old_cpu.itime,
			new_cpu.iowtime - old_cpu.iowtime,
			new_cpu.irqtime - old_cpu.irqtime,
			new_cpu.sirqtime - old_cpu.sirqtime,
			total_delta_time);
	printf("\n");
	if (!threads) 
		printf("%5s %4s %1s %5s %7s %7s %3s %-8s %s\n", "PID", "CPU%", "S", "#THR", "VSS", "RSS", "PCY", "UID", "Name");
	else
		printf("%5s %5s %4s %1s %7s %7s %3s %-8s %-15s %s\n", "PID", "TID", "CPU%", "S", "VSS", "RSS", "PCY", "UID", "Thread", "Proc");

	for (i = 0; i < num_new_procs; i++) {
		proc = new_procs[i];

		if (!proc || (max_procs && (i >= max_procs)))
			break;
		user  = getpwuid(proc->uid);
		group = getgrgid(proc->gid);
		if (user && user->pw_name) {
			user_str = user->pw_name;
		} else {
			snprintf(user_buf, 20, "%d", proc->uid);
			user_str = user_buf;
		}
		if (group && group->gr_name) {
			group_str = group->gr_name;
		} else {
			snprintf(group_buf, 20, "%d", proc->gid);
			group_str = group_buf;
		}
		if (!threads) 
			printf("%5d %3ld%% %c %5d %6ldK %6ldK %3s %-8.8s %s\n", proc->pid, proc->delta_time * 100 / total_delta_time, proc->state, proc->num_threads,
					proc->vss / 1024, proc->rss * getpagesize() / 1024, proc->policy, user_str, proc->name[0] != 0 ? proc->name : proc->tname);
		else
			printf("%5d %5d %3ld%% %c %6ldK %6ldK %3s %-8.8s %-15s %s\n", proc->pid, proc->tid, proc->delta_time * 100 / total_delta_time, proc->state,
					proc->vss / 1024, proc->rss * getpagesize() / 1024, proc->policy, user_str, proc->tname, proc->name);
	}
}

static struct proc_info *find_old_proc(pid_t pid, pid_t tid) {
	int i;

	for (i = 0; i < num_old_procs; i++)
		if (old_procs[i] && (old_procs[i]->pid == pid) && (old_procs[i]->tid == tid))
			return old_procs[i];

	return NULL;
}

static void free_old_procs(void) {
	int i;

	for (i = 0; i < num_old_procs; i++)
		if (old_procs[i])
			free_proc(old_procs[i]);

	free(old_procs);
}

static int proc_cpu_cmp(const void *a, const void *b) {
	struct proc_info *pa, *pb;

	pa = *((struct proc_info **)a); pb = *((struct proc_info **)b);

	if (!pa && !pb) return 0;
	if (!pa) return 1;
	if (!pb) return -1;

	return -numcmp(pa->delta_time, pb->delta_time);
}

static int proc_vss_cmp(const void *a, const void *b) {
	struct proc_info *pa, *pb;

	pa = *((struct proc_info **)a); pb = *((struct proc_info **)b);

	if (!pa && !pb) return 0;
	if (!pa) return 1;
	if (!pb) return -1;

	return -numcmp(pa->vss, pb->vss);
}

static int proc_rss_cmp(const void *a, const void *b) {
	struct proc_info *pa, *pb;

	pa = *((struct proc_info **)a); pb = *((struct proc_info **)b);

	if (!pa && !pb) return 0;
	if (!pa) return 1;
	if (!pb) return -1;

	return -numcmp(pa->rss, pb->rss);
}

static int proc_thr_cmp(const void *a, const void *b) {
	struct proc_info *pa, *pb;

	pa = *((struct proc_info **)a); pb = *((struct proc_info **)b);

	if (!pa && !pb) return 0;
	if (!pa) return 1;
	if (!pb) return -1;

	return -numcmp(pa->num_threads, pb->num_threads);
}

static int numcmp(long long a, long long b) {
	if (a < b) return -1;
	if (a > b) return 1;
	return 0;
}

static void usage(char *cmd) {
	fprintf(stderr, "Usage: %s [ -m max_procs ] [ -n iterations ] [ -d delay ] [ -s sort_column ] [ -t ] [ -h ]\n"
			"    -m num  Maximum number of processes to display.\n"
			"    -n num  Updates to show before exiting.\n"
			"    -d num  Seconds to wait between updates.\n"
			"    -s col  Column to sort by (cpu,vss,rss,thr).\n"
			"    -t      Show threads instead of processes.\n"
			"    -h      Display this help screen.\n",
			cmd);
}
